Rf lens antenna array with reduced grating lobes

ABSTRACT

A radio frequency antenna array uses lenses and RF elements, to provide ground-based coverage for cellular communication. The antenna array can include a spherical lens, where each spherical lens has at least two associated RF elements. Each of the RF elements associated with a given lens produces an output beam with an output area. The antenna includes a control mechanism configured to enable a user to move the RF elements along their respective tracks, and automatically phase compensate the output beams produced by the RF elements based on the relative distance between the RF elements.

This application is a continuation-in-part of co-pending U.S.Non-Provisional application Ser. No. 17/404,518, filed Aug. 17, 2021,which is a continuation-in-part of co-pending U.S. Non-Provisionalapplication Ser. No. 17/334,507, filed May 28, 2021, which is acontinuation-in-part of co-pending U.S. Non-Provisional application Ser.No. 17/115,718, filed Dec. 8, 2020, which is a continuation-in-part ofU.S. Pat. No. 11,050,157 filed Oct. 30, 2020, which is acontinuation-in-part of co-pending U.S. Pat. No. 10,931,021 filed Jan.10, 2020, which is a continuation of U.S. Pat. No. 10,559,886, filed May24, 2019, which is a continuation-in-part of U.S. Pat. No. 10,326,208,filed Dec. 3, 2018, which is a continuation of U.S. Pat. No. 10,224,636,filed Sep. 8, 2017, which is a continuation of U.S. Pat. No. 10,224,635,filed Oct. 10, 2016, which is a continuation of U.S. Pat. No. 9,728,860,filed Dec. 3, 2015, which claims the benefit of U.S. ProvisionalApplication No. 62/201523 filed Aug. 5, 2015. This and all otherreferenced extrinsic materials are incorporated herein by reference intheir entirety. Where a definition or use of a term in a reference thatis incorporated by reference is inconsistent or contrary to thedefinition of that term provided herein, the definition of that termprovided herein is deemed to be controlling.

FIELD OF THE INVENTION

The field of the invention is radio frequency antenna technology.

BACKGROUND

The following description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed invention, or that any publication specifically orimplicitly referenced is prior art.

In many cases, capacity in a wireless network can be increased by: 1)adding to the number of nodes in the network, 2) providing increasedfrequency coverage (e.g. wider bandwidths), or 3) improving the airinterface method to increase data throughput. However, the second andthird approaches generally rely on advances outside the networkoperator's control. For example, the acquisition and utilization ofwider bandwidths depend on local governments granting new licenses for agiven section of the RF spectrum. Further, improved air interfacemethods are typically developed outside the Research and Developmentprocesses of the network operators. As such, network operators canchoose to split cells this cell splitting has been a known step inincreasing network capacity since cellular networks were invented in the1970s. However, new cells historically meant the necessity of a new sitealong with the associated complexity and costs. Another knownalternative process is to increase the number of sectors at a given cellsite. This alternative process could be accomplished by addingadditional antennas at a given site, or by using common aperturemulti-beam antennas.

However, a drawback of multiple beam antennas is poor beam to beamisolation. Beam isolation is calculated by the amount of impingingsignals produced by beams adjacent to that beam assigned to a receiver.From a transmit view, beam isolation is a representation of the amountof unwanted signal transmitted into the wrong beam. There are two majorcontributors to beam to beam isolation: 1) coupling from non-radiatingfeed network components (e.g. Butler matrix), and 2) coupling fromradiating network components (e.g. radiating beams). Also, while aButler Matrix itself typically has directivity of roughly 20 dB, whenadded to the azimuth side lobes it results in poor beam to beamisolation of roughly 15 dB for a multiple beam antenna.

In contrast, multi-lens based antenna arrays have superior performancein several key performance metrics compared to aforementioned antennasystems including: 1) the ability to provide large electrical down tiltangles for the main output beam while configured to maintain gain, beamwidth, cross polarization discrimination (cross-pol), and side lobelevels (SLL), 2) a reduction in the number of radiating elementscompared to non-lens based antennas , 3) a higher antenna efficiency, 4)an ability to form multiple beam arrays using a common aperture withoututilizing a Butler Matrix.

Multiple beam, multi-lens antenna arrays are very useful in 4G and 5Gwireless networks as they increase capacity while maintaining antennasize and volumes similar to single beam antennas and are easily combinedin multiple column arrays for 4×4 multiple input/multiple output (MIMO).However, a limitation of all multiple beam antenna arrays are the sidelobes (SLL) in the azimuth plane. As the azimuth SLL increases, thenetwork has a more difficult time discriminating between output beams.Voltage Standing Wave Ratio (VSWR) alarms, coupled to the RF elements,are based on power received due to a transmitter signal, such that whena multiple beam antenna has poor beam to beam isolation, a transmitpower imbalance between beams due to higher traffic into a beam cancause VSWR alarms. This is a major drawback to multiple beam antennas.

FIG. 6 of the prior art, U.S. Pat. No. 8,311,582 to Trigui et. al.,depicts a two-beam antenna system with poor azimuth side lobe levels.The antenna described in Trigui uses a Butler Matrix, an RF networkdevice that when applied to multiple beam antennas comprises N inputsand M outputs (i.e. an NxM Butler Matrix). The M outputs each feed oneRF element of the array, such that the elements that are arrayed in theazimuth plane. In FIG. 6, M=3. The N inputs each produce a separate beamby creating a distinct phasing between the M outputs for each input.Here, N=2 for the dual beam antenna using a Butler Matrix. FIG. 6 ofTrigui is an example of a multiple beam antenna based on a 2×3 ButlerMatrix with inherently poor beam to beam isolation (e.g. roughly 15 dB).

Upper side lobes are undesirable in the vertical plane. To reduce sidelobes vertically oriented linear arrays taper amplitude and phase acrossthe RF elements, typically with highest amplitude in the centerelements. Grating lobes occur whenever the spacing between elements isless than one half wavelength. Grating lobes are reduced by theamplitude taper of the individual elements in the vertical plane. As anexample, if a grating lobe occurs at 60 degrees from the beam peak andthe element pattern is down 10 dB at 60 degrees the grating lobe will beattenuated by 10 dB. This effect is more pronounced when the arrayelements are lenses due to the narrower element pattern from a typicalRF lens. Lens spacings of over two wavelengths are possible withstandard tilt and side lobe levels. These two techniques, amplitude andphase taper between elements and reducing grating lobes by elementpattern power roll off, are used extensively in base station antennadesign.

The novel technique described here presents a method to further reducegrating lobes. In a preferred embodiment, the vertical pattern for BaseStation Antennas consists of reduced side lobes above the beam peak andhigher side lobes below the beam peak with negligible reduction indirectivity, compared to no side lobe mitigation. Antennas on a typicaltower want low upper side lobes to reduce interference to other cellswhile providing as much pattern as possible near in to the tower. Bydown tilting the individual elements at a tilt larger than the tiltproduced by the relative phase between the elements the element patternis positioned for greater attenuation above the main beam and lessattenuation below the main beam. This “pre-tilt” technique consists oflimitless variations of how much pre-tilt for each element in the array,creating different pre-tilt for different elements of the array, andkeeping some elements at a fixed tilt over the range of antenna tilts.Advantageously, this technique can be used for any antenna array butwhen RF lens arrays are used more significant performance improvement ispossible due to the narrow element patterns.

RF lens-based antenna sub-systems find wide use outside the area ofwireless communication systems for the reasons previously mentioned; lowweight, superior beam isolation, consistent performance over scan angle.The use of RF lens-based antenna sub-systems in satellite trackingsystems is a recent area of industry focus.

The scalable approach described here extends the teaching of satellitetracking to include a switched beam system that does not require rapidrepositioning of beams, but instead relies on the rapid switchingbetween beams located at different positions and with higher resolution.This approach uses low noise amplifiers (LNAs) and transmit amplifierswith RF switching and distribution systems to place the output area ofan output beam in a desired location, without the use of phase shifters.In place of phase shifters that provide continuous scanning, a switchedbeam architecture is presented, providing higher performance byaccurately configuring multiple output beams using highly reliableswitching techniques. In the receive path, the Low Noise Amplifiers(LNAs) limit the deterioration in the signal to noise (S/N) ratio whichkeeps a high signal integrity through the RF switching and distributionmatrix.

Phase shifters are used when beam position needs to be finely tuned to aspecific location. When multiple emitters are to be tracked a moreefficient method of tracking is to provide a cluster of high gain,narrow beam width beams, placing the emitters in a given beams' outputarea, which can be scaled to even more narrow beams by arraying togetherlenses with beams pointing in the same area of the sky.

The tracking of RF signal emitters (e.g. satellites, aircraft, missiles,etc.) has evolved over many decades. The goal of these RF signaltracking systems is to acquire the emitters RF signal, pinpoint the lookangle (e.g. elevation and azimuth), and maintain tracking as the emittermoves relative to the receiver. Several proven techniques exist. Oneexample technique is the Monopulse technique, where position isdetermined through a feedback system keeping the object in the center ofthe difference pattern. Another example are the giant PAVE-PAWS radars,installed strategically around the northern hemisphere, that are capableof tracking numerous high velocity emitters simultaneously. These twoexamples highlight the tradeoff between nimble tracking of a singleemitter (e.g. monopulse) and the ability to track many emitterssimultaneously (e.g. PAVE-PAWS). RF emitter tracking systems are ofteninstalled on aircraft, ships, and vehicles where size, weight, windload, and structural considerations are paramount.

SUMMARY OF THE INVENTION

The inventive subject matter provides apparatus, systems and methods inwhich an antenna uses an array of spherical lenses in a staggeredarrangement to reduce azimuth side lobe levels. Lens based antennasusing light weight dielectric material have seen a growing market forseveral applications including base station antennas, stadium antennas,special event antennas, and satellite tracking antennas. In general, theside lobes generated by a given antenna are unwanted. One exception areside lobes in the vertical plane below the main beam. These side lobeshelp provide coverage near into the tower, in the case of base stationantennas. Any technique that can reduce unwanted side lobes with minimalimpact on other antenna parameters such as gain, beam widths, crosspolarization levels, would likely be advantageous for the operation oflens based antennas.

Numerous techniques exist to reduce side lobes. However, the specifictechnique utilized depends on the type of antenna. All techniques arebased on antenna theory that teaches the far field pattern is theFourier Transform of the near field pattern. The Fourier Transform of astep function, which can be thought of as 1) no power, 2) then equalpower over distance, then 3) no power, as a sin x/x function. Thisrepresents the worst-case side lobe scenario. In a real-life antennathis corresponds to having no tapering of amplitude or phase over theaperture or equivalent, such as constant amplitude across a set ofelement in an array. Conversely, the Fourier Transform of a Gaussiandistribution is another Gaussian distribution which represents theabsence of all side lobes. This means the more a set of amplitude andphase coefficients representing the amplitude and phase components ofthe array elements can conform to a Gaussian distribution the lower theside lobes. Various other techniques have been developed for optimaltrade-off in antenna arrays between the amplitude and phase tapersacross the elements and the far-field side lobes, including a techniqueusing Tchebychev polynomials.

These phase tapering techniques only apply to arrays with three or moreelements. You cannot taper a two-element array. Another common side lobewhere tapering techniques have no effect is the grating lobe caused whenelements of an array are spaced more than one half wavelength apart. Animportant advantage using RF lens-based antenna arrays is that thelenses, fed by one or more RF elements, can be spaced much wider thanone half wavelength. In a preferred embodiment, the lenses are spaced atleast two wavelengths apart. The reason for this is the grating lobe isattenuated by the element pattern that is much narrower than aconventional antenna array that does not use RF lenses. This behavior ofRF lens-based antenna arrays has led to the technique described wherecreating an otherwise undesirable “pre-tilt” reduces the upper gratinglobe.

The other technique described here involves designing RF lens arrayswhere the RF element remains fixed. This is a straightforward techniqueused in traditional base station antennas, but can be useful in RFlens-based antenna arrays over a limited scan range when thearchitecture of the antenna does not allow for movement of the elementsand limited tilt range is acceptable.

Various objects, features, aspects and advantages of the inventivesubject matter will become more apparent from the following detaileddescription of preferred embodiments, along with the accompanyingdrawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates an exemplary antenna system.

FIG. 1B illustrates an exemplary control mechanism.

FIGS. 2A and 2B illustrate the front and back perspectives,respectively, of a spherical lens having one-dimensional tracks.

FIG. 3 illustrates an alternative antenna system having two-dimensionaltracks.

FIGS. 4A and 4B illustrate the front and back perspectives,respectively, of a spherical lens having a two-dimensional track.

FIG. 5 illustrates an antenna that pairs opposite RF elements in thesame group.

FIG. 6 illustrates another antenna that pairs opposite RF elements inthe same group.

FIG. 7A illustrates an antenna array with a first and a second lens,each producing output beams via their RF element.

FIG. 7B illustrates the output areas of the first and second lenses.

FIG. 8A illustrates the placement of RF elements on multiple lenses inan antenna array.

FIG. 8B illustrates the operation of output areas in various output areagroupings.

FIG. 9 illustrates an antenna arrangement with a first, a second, and athird lens, each producing output beams via their RF elements.

FIG. 10 illustrates an alternative antenna system with a first, asecond, and a third lens in a staggered arrangement.

FIG. 11A illustrates the top down perspective of an alternative antennasystem with a first, a second, and a third lens in a staggeredarrangement.

FIG. 11B illustrates the front-facing perspective of an alternativeantenna system with a first, a second, and a third lens in a staggeredarrangement.

FIG. 11C illustrates the side-view perspective of an alternative antennasystem with a first, a second, and a third lens in a staggeredarrangement.

FIG. 12 illustrates the operation of an alternative antenna systemdepicted in FIG. 10.

FIGS. 13A and B illustrate the alternative antenna system of FIG. 10with a first, a second, a third, and a fourth lens in a staggeredarrangement.

FIG. 14 illustrates an antenna array in a staggered arrangement, withdielectric blocks.

FIG. 15 illustrates an alternative antenna array with a first and asecond lens, each producing output beams via their RF element.

FIG. 16 illustrates an antenna arrangement with a six lenses, eachproducing output beams via their RF elements, in a beam switchingconfiguration.

FIG. 17 illustrates an antenna arrangement with three sets of RFelements around each of two lenses.

FIG. 18 illustrates an antenna arrangement with three RF lenses wherethe feeds illuminating the lenses are positioned to provide a fixed“pre-tilt”.

FIG. 19 illustrates an antenna system, with a single RF element.

FIG. 20 illustrates the front-facing perspective of an alternativeantenna system with a dual RF element.

DETAILED DESCRIPTION

Throughout the following discussion, numerous references will be maderegarding servers, services, interfaces, engines, modules, clients,peers, portals, platforms, or other systems formed from computingdevices. It should be appreciated that the use of such terms is deemedto represent one or more computing devices having at least one processor(e.g., ASIC, FPGA, DSP, x86, ARM, ColdFire, GPU, multi-core processors,etc.) configured to execute software instructions stored on a computerreadable tangible, non-transitory medium (e.g., hard drive, solid statedrive, RAM, flash, ROM, etc.). For example, a server can include one ormore computers operating as a web server, database server, or other typeof computer server in a manner to fulfill described roles,responsibilities, or functions. One should further appreciate thedisclosed computer-based algorithms, processes, methods, or other typesof instruction sets can be embodied as a computer program productcomprising a non-transitory, tangible computer readable media storingthe instructions that cause a processor to execute the disclosed steps.The various servers, systems, databases, or interfaces can exchange datausing standardized protocols or algorithms, possibly based on HTTP,HTTPS, AES, public-private key exchanges, web service APIs, knownfinancial transaction protocols, or other electronic informationexchanging methods. Data exchanges can be conducted over apacket-switched network, a circuit-switched network, the Internet, LAN,WAN, VPN, or other type of network.

As used in the description herein and throughout the claims that follow,when a system, engine, or a module is described as configured to performa set of functions, the meaning of “configured to” or “programmed to” isdefined as one or more processors being programmed by a set of softwareinstructions to perform the set of functions.

The following discussion provides example embodiments of the inventivesubject matter. Although each embodiment represents a single combinationof inventive elements, the inventive subject matter is considered toinclude all possible combinations of the disclosed elements. Thus if oneembodiment comprises elements A, B, and C, and a second embodimentcomprises elements B and D, then the inventive subject matter is alsoconsidered to include other remaining combinations of A, B, C, or D,even if not explicitly disclosed.

As used herein, and unless the context dictates otherwise, the term“coupled to” is intended to include both direct coupling (in which twoelements that are coupled to each other contact each other) and indirectcoupling (in which at least one additional element is located betweenthe two elements). Therefore, the terms “coupled to” and “coupled with”are used synonymously.

As used herein, and unless the context dictates otherwise, the term“stagger” is defined as the perpendicular offset between at least twovirtual axis'.

In some embodiments, the numbers expressing quantities of ingredients,properties such as concentration, reaction conditions, and so forth,used to describe and claim certain embodiments of the inventive subjectmatter are to be understood as being modified in some instances by theterm “about.” Accordingly, in some embodiments, the numerical parametersset forth in the written description and attached claims areapproximations that can vary depending upon the desired propertiessought to be obtained by a particular embodiment. In some embodiments,the numerical parameters should be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of some embodiments of the inventivesubject matter are approximations, the numerical values set forth in thespecific examples are reported as precisely as practicable. Thenumerical values presented in some embodiments of the inventive subjectmatter may contain certain errors necessarily resulting from thestandard deviation found in their respective testing measurements.

As used in the description herein and throughout the claims that follow,the meaning of “a,” “an,” and “the” includes plural reference unless thecontext clearly dictates otherwise. Also, as used in the descriptionherein, the meaning of “in” includes “in” and “on” unless the contextclearly dictates otherwise.

Unless the context dictates the contrary, all ranges set forth hereinshould be interpreted as being inclusive of their endpoints andopen-ended ranges should be interpreted to include only commerciallypractical values. The recitation of ranges of values herein is merelyintended to serve as a shorthand method of referring individually toeach separate value falling within the range. Unless otherwise indicatedherein, each individual value within a range is incorporated into thespecification as if it were individually recited herein. Similarly, alllists of values should be considered as inclusive of intermediate valuesunless the context indicates the contrary.

All methods described herein can be performed in any suitable orderunless otherwise indicated herein or otherwise clearly contradicted bycontext. The use of any and all examples, or exemplary language (e.g.“such as”) provided with respect to certain embodiments herein isintended merely to better illuminate the inventive subject matter anddoes not pose a limitation on the scope of the inventive subject matterotherwise claimed. No language in the specification should be construedas indicating any non-claimed element essential to the practice of theinventive subject matter.

Groupings of alternative elements or embodiments of the inventivesubject matter disclosed herein are not to be construed as limitations.Each group member can be referred to and claimed individually or in anycombination with other members of the group or other elements foundherein. One or more members of a group can be included in, or deletedfrom, a group for reasons of convenience and/or patentability. When anysuch inclusion or deletion occurs, the specification is herein deemed tocontain the group as modified thus fulfilling the written description ofall Markush groups used in the appended claims.

In one aspect of the inventive subject matter, an antenna uses an arrayof spherical lens and mechanically movable elements along the surface ofthe spherical lens to provide coverage for a small, focused geographicalarea. In some embodiments, the antenna includes at least two sphericallens aligned along a virtual axis. The antenna also includes an elementassembly for each spherical lens. Each element assembly has at least onetrack that curves along the contour of the exterior surface of thespherical lens and along which a radio frequency (RF) element can move.In preferred embodiments, the track allows the RF element to move in adirection that is parallel to the virtual axis. The antenna alsoincludes a phase shifter that is configured to adjust a phase of thesignals produced by the RF elements. The antenna includes a controlmechanism that is connected to the phase shifter and the RF elements.The control mechanism is configured to enable a user to move the RFelements along their respective tracks, and automatically configure thephase shifter to modify a phase of the output signals from the elementsbased on the relative positions between the RF elements.

FIG. 1A illustrates an antenna system 100 according to some embodimentsof the inventive subject matter. In this example, the antenna system 100includes two spherical lenses 105 and 110 that are aligned along avirtual axis 115 in a three-dimensional space. It is noted that althoughonly two spherical lenses are shown in this example, more spherical lenscan be aligned along the virtual axis 115 in the antenna system 100. Aspherical lens is a lens with a surface having a shape of (orsubstantially having a shape of) a sphere. As defined herein, a lenswith a surface that substantially conform to the shape of a sphere meansat least 50% (preferably at least 80%, and even more preferably at least90%) of the surface area conforms to the shape of a sphere. Examples ofspherical lenses include a spherical-shell lens, the Luneburg lens, etc.The spherical lens can include only one layer of dielectric material, ormultiple layers of dielectric material. A conventional Luneburg lens isa spherically symmetric lens that has multiple layers inside the spherewith varying indices of refraction.

The antenna system 100 also includes an element assembly 120 associatedwith the spherical lens 105, and an element assembly 125 associated withthe spherical lens 110. Each element assembly includes at least onetrack. In this example, the element assembly 120 includes a track 130while the element assembly 125 includes a track 135. As shown, each ofthe tracks 130 and 135 has a shape that substantially conforms to(curves along) the exterior surface of its associated spherical lens.The tracks 130 and 135 can vary in length and in dimensions. In thisexample, the tracks 130 and 135 are one-dimensional and oriented alongthe virtual axis 115. In addition, each of the tracks 130 and 135 coversless than half of a circle created by the respective spherical lens.However, it is contemplated that the tracks 130 and 135 can havedifferent orientation (e.g., oriented in perpendicular to the virtualaxis 115, etc.), can be two-dimensional (or multi-dimensional), and/orcan cover smaller or larger portions of the surface areas of thespherical lenses 105 and 110 (e.g., covering a circumference of a circlecreated by the spherical lenses 105 and 110, covering a hemisphericalarea of the spherical lenses 105 and 110, etc.).

Each of the element assemblies 120 and 125 also houses at least one RFelement. An RF element can include an emitter, a receiver, or atransceiver. As shown, the element assembly 120 houses an RF element 140on the track 130, and the element assembly 125 houses an RF element 145on the track 135. In this example, each of the element assemblies 120and 125 only includes one RF element, but it has been contemplated thateach element assembly can house multiple RF elements on one or moretracks.

In exemplary embodiments, each RF element (from RF elements 140 and 145)is configured to transmit an output signal (e.g., a radio frequencysignal) in the form of a beam to the atmosphere through itscorresponding spherical lens. The spherical lens allows the output RFsignal to narrow so that the resultant beam can travel a fartherdistance. In addition, the RF elements 140 and 145 are configured toreceive/detect incoming signals that have been focused by the sphericalspheres 105 and 110.

Each RF element (of the RF elements 140 and 145) is physically connectedto (or alternatively, communicatively coupled with) a phase shifter formodifying a phase of the output RF signal. In this example, the RFelement 140 is communicatively coupled to a phase shifter 150 and the RFelement 145 is communicatively coupled to a phase shifter 155. The phaseshifters 150 and 155 are in turn physically connected to (oralternatively, communicatively coupled with) a control mechanism 160.

The control mechanism 160 includes a mechanical module configured toenable a user to mechanically move the RF elements 140 and 145 along thetracks 130 and 135, respectively. The interface that allows the user tomove the RF elements can be a mechanical rod or other physical trigger.It is noted that the mechanical rod can have a shape such as a cylinder,a flat piece of dielectric material, or any kind of elongated shapes. Insome embodiments, the control mechanism 160 also includes an electronicdevice having at least one processor and memory that stores softwareinstructions, that when executed by the processor, perform the functionsand features of the control mechanism 160. The electronic device of someembodiments is programmed to control the movement of the RF elements 140and 145 along the tracks 130 and 135, respectively. The electronicdevice can also provide a user interface (e.g., a graphical userinterface displayed on a display device, etc.) that enables the user tocontrol the movement of the RF elements 140 and 145. The electronicdevice can in turn be connected to a motor that controls the mechanicalmodule. Thus, the motor triggers the mechanical module upon receiving asignal from the electronic device.

For example, the control mechanism 160 can move the RF element 140 fromposition ‘a’ (indicated by dotted-line circle) to position ‘b’(indicated by solid-line circle) along the track 130, and move the RFelement 145 from position ‘c’ (indicated by dotted-line circle) toposition ‘d’ (indicated by solid-line circle) along the track 135. Bymoving the RF elements to different positions, the antenna system 100can dynamically change the geographical coverage area of the antenna100. It is also contemplated that by moving multiple RF elements andarranging them in different positions, the antenna system 100 can alsodynamically change the coverage size, and capacity allocated todifferent geographical areas. As such, the antenna system 100, via thecontrol mechanism 160, can be programmed to configure the RF elements toprovide coverage at different geographical areas and different capacity(by having more or less RF elements covering the same geographical area)depending on demands at the time.

For example, as the control mechanism 160 moves the RF elements 140 and145 from positions ‘a’ and ‘c’ to positions ‘b’ and ‘d,’ respectively,the antenna system 100 can change the geographical coverage area to anarea that is closer to the antenna system 100. It is also noted thathaving multiple spherical lenses with associated RF element allow theantenna system 100 to (1) provide multiple coverage areas and/or (2)increase the capacity within a coverage area. In this example, sinceboth of the RF elements 140 and 145 associated with the spherical lenses105 and 110 are directing resultant output signal beams at the samedirection as indicated by arrows 165 and 170

However, it is noted that in an antenna system where multiple sphericallenses are aligned with each other along a virtual axis (e.g., thevirtual axis 115), when multiple RF elements are transmitting output RFsignals through the multiple spherical lenses at an angle that is notperpendicular to the virtual axis along which the spherical lenses arealigned, the signals from the different RF elements will be out ofphase. In this example, it is shown from the dotted lines 175 -185 thatthe output signals transmitted by the RF elements 140 and 145 atpositions ‘b’ and ‘d,’ respectively, are out of phase. Dotted lines 175185 are virtual lines that are perpendicular to the direction of theresultant output signal beams transmitted from RF elements 140 and 145at positions ‘b’ and ‘d,’ respectively. As such, dotted lines 175 185indicate positions of advancement for the resultant output beams. Whenthe output signal beams are in phase, the output signal beams shouldhave the same progression at each of the positions 175 185. Assumingboth RF elements 140 and 145 transmit the same output signal at the sametime, without any phase adjustments, the output signal beams 165 and 170would have the same phase at the time they leave the spherical lenses105 and 110, respectively. As shown, due to the directions the beams aretransmitted with respect to how the spherical lenses 105 and 110 arealigned (i.e., the orientation of the virtual axis 115), the position175 is equivalent to the edge of the spherical lens 105 for the signalbeam 165, but is equivalent to the center of the spherical lens 110 forthe signal beam 170. Similarly, the position 180 is away from the edgeof the spherical lens 105 for a distance ‘e’ while the position 180 isequivalent to the edge of the spherical lens 110. As such, in order tomake the signal beams 165 and 170 in phase, the control mechanism 160configures the phase shifters 150 and 155 to modify (or adjust) thephase of the output signal transmitted by either RF element 140 or 145,or both output signals transmitted by RF elements 140 and 145. In thisexample, the control mechanism 160 can adjust the phase of the outputsignal transmitted by RF element 145 by a value equivalent to thedistance ‘e’ such that output signal beams 165 and 170 are in-phase.

In other embodiments, the control mechanism 160 is configured toautomatically determine the phase modifications necessary to bring theoutput beams in-phase based on the positions of the RF elements. It iscontemplated that a user can provide an input of a geographical areas tobe covered by the antenna system 100 and the control mechanism 160 wouldautomatically move the positions of the RF elements to cover thegeographical areas and configure the phase shifters to ensure that theoutput beams from the RF elements are in phase based on the newpositions of the RF elements.

FIG. 1B illustrates an example of a control mechanism 102 attached tothe element assembly 103 that is associated with the spherical lens 107.The mechanical module 102 includes a housing 104, within which a rod 106is disposed. The rod 106 has teeth 108 configured to rotate a gear 112.The gear can in turn control the movement of the RF element 109. Underthis setup, a person can manually adjust the position of the RF element109 by moving the rod 106 up and down. It has been contemplated that therod 106 can be extended to reach other element assemblies (for example,an element assembly and spherical lens that are stacked on top of thespherical lens 107). That way, the rod can effectively control themovement of RF elements associated with more than one spherical lens.

A phase shifter can be implemented within the same mechanism 102, byintegrating the rod 106 into the phase shifter design. When the rod isintegrated into the phase shifter, adjusting the position of the rod 106in this manner modifies the phase of an output signal transmitted by theRF element 109. It is noted that one can configure the position of therod 106 and the gear 112 such that the position of the RF element 109and the phase modification is in-sync. This way, one can simply providea single input (moving the rod up or down by a distance) to adjust boththe position of the RF element 109 and the phase of the output signal.

It is also contemplated that an electric device (not shown) can beconnected to the end of the rod (not attached to the gear 112). Theelectric device can control the movement of the rod 106 based on aninput electronic signal, thereby controlling the movement of the RFelement 109 and the phase adjustment of the output signal. A computingdevice (not shown) can communicatively couple with the electric deviceto remotely control the RF element 109 and the phase of the outputsignal.

FIGS. 2A and 2B illustrate the spherical lens 105 and the elementassembly 120 from different perspectives. Specifically, FIG. 2Aillustrates the spherical lens 105 from a front perspective, in whichthe element assembly 120 (including the track 130 and the RF element140) appear to be behind the spherical lens 105. In this figure, thesignals emitting from the RF element 140 are directed outward from thepage. FIG. 2B illustrates the spherical lens 105 from a backperspective, in which the element assembly 120 (including the track 130and the RF element 140) appear to be behind the spherical lens 105. Inthis figure, the signals emitting from the RF element 140 are directedinto the page.

FIG. 3 illustrates an antenna 300 in which the tracks associated withthe spherical lens are two dimensional and each track associated with aspherical lens includes two RF elements. The antenna 300 is similar tothe antenna 100 of FIG. 1. As shown, the antenna 300 has two sphericallenses 305 and 310 aligned along a virtual axis 315 in athree-dimensional space. The spherical lens 305 has an associatedelement assembly 320, and the spherical lens 310 has an associatedelement assembly 325. The element assembly 320 has a track 330, andsimilarly, the element assembly 325 has a track 335. The tracks 330 and335 are two dimensional.

In addition, each of the tracks 330 and 335 includes two RF elements. Asshown, the track 330 has RF elements 340 and 345, and the track 335 hasRF elements 350 and 355. The two dimensional tracks 330 and 335 allowsthe RF elements 340 355 to move in a two dimensional field in theirrespective tracks. In exemplary embodiments, the antenna 300 createsgroups of RF elements, where each group consists of one RF element fromeach element assembly. In this example, the antenna 300 has two groupsof RF elements. The first group of RF elements includes the RF element340 of the element assembly 320 and the RF element 350 of the elementassembly 325. The second group of RF elements includes the RF element345 of the element assembly 320 and the RF element 355 of the elementassembly 325. The antenna 300 provides a control mechanism and phaseshifter for each group of RF elements. In this example, the antenna 300provides a control mechanism and phase shifter 360 (all in one assembly)for the first group of RF elements and a control mechanism and phaseshifter 365 for the second group of RF elements. The control mechanismand phase shifters are configured to modify the positions of the RFelements within the group and to modify the phase of the output signalstransmitted by the RF elements in the group such that the output signalscoming out for the respective spherical lens 305 and 310 are in-phase.

FIGS. 4A and 4B illustrates the spherical lens 305 and its elementassembly 320 from different perspectives. Specifically, FIG. 4Aillustrates the spherical lens 305 from a front perspective, in whichthe element assembly 320 (including the track 330 and the RF elements340 and 345) appear to be behind the spherical lens 305. In this figure,the signals emitting from the RF element 340 and 345 are directedoutward from the page. As shown, the RF elements 340 and 345 can move upand down (parallel to the virtual axis 315) or sideways (perpendicularto the virtual axis 315), as shown by the arrows near the RF element340.

FIG. 4B illustrates the spherical lens 305 from a back perspective, inwhich the element assembly 320 (including the track 330 and the RFelements 340 and 345) appear to be behind the spherical lens 305. Inthis figure, the signals emitting from the RF elements 340 and 345 aredirected into the page. It is contemplated that more than two RFelements can be installed in the same element assembly, and differentpatterns (e.g., 3×3, 4×3, 4×4, etc.) of RF element arrangements can beformed on the element assembly.

Referring back to FIG. 3, it is noted that the RF elements that are insubstantially identical positions with respect to their respectivespherical lens are grouped together. For example, the RF element 340 ispaired with the RF element 350 because their positions relative to theirrespective associated spherical lenses 305 and 310 are substantiallysimilar. Similarly, the RF element 345 is paired with the RF element 355because their positions relative to their respective associatedspherical lenses 305 and 310 are substantially similar. It iscontemplated that the manner in which RF elements are paired can affectthe vertical footprint of the resultant beam (also known as polarizedcoincident radiation pattern) generated by the RF elements. As definedherein, the vertical footprint of an RF element means the coverage areaof the RF element on a dimension that is parallel to the axis alongwhich the spherical lenses are aligned. For practical purposes, the goalis to maximize the overlapping areas (also known as the cross polarizedcoincident radiation patterns) of the different resultant beamsgenerated by multiple RF elements.

As such, in another aspect of the inventive subject matter, an antennahaving an array of spherical lenses pairs opposite RF elements that areassociated with different spherical lenses to cover substantiallyoverlapping geographical areas. In some embodiments, each spherical lensin the array of spherical lenses has a virtual axis that is parallelwith other virtual axes associated with the other spherical lenses inthe array. One of the paired RF elements is placed on one side of thevirtual axis associated with a first spherical lens and the other one ofthe paired RF elements is placed on the opposite side of the virtualaxis associated with a second spherical lens. In preferred embodiments,the antenna also includes a control mechanism programmed to configurethe paired RF elements to provide output signals to and/or receive inputsignals from substantially overlapping geographical areas.

FIG. 5 illustrates an example of such an antenna 500 of preferredembodiments. The antenna 500 includes an array of spherical lens(including spherical lenses 505 and 510) that is aligned along an axis515. Although the antenna 500 in this example is shown to include onlytwo spherical lenses in the array of spherical lenses, it has beencontemplated that the antenna 500 can include more spherical lenses thatare aligned along the axis 515 as desired.

Each spherical lens also includes an RF element arrangement axis that isparallel to one another. In this example, the spherical lens 505 has anRF element arrangement axis 540 and the spherical lens 510 has an RFelement arrangement axis 545. Preferably, the RF element arrangementaxes 540 and 545 are perpendicular to the virtual axis 515 along whichthe spherical lenses 505 and 510 are aligned, as shown in this example.However, it has been contemplated that the RF element arrangement axescan be in any orientation, as long as they are parallel with each other.

As shown, each spherical lens in the array has associated RF elements.In this example, the spherical lens 505 has two associated RF elements520 and 525, and the spherical lens 510 has two associated RF elements530 and 535. The RF elements associated with each spherical lens areplaced along the surface of the spherical lens, on different sides ofthe RF element arrangement axis. As shown, the RF element 520 is placedon top of (on one side of) the RF element arrangement axis 540 and theRF element 525 is placed on the bottom of (on the other side of) the RFelement arrangement axis 540. Similarly, the RF element 530 is placed ontop of (on one side of) the RF element arrangement axis 545 and the RFelement 535 is placed on the bottom of (on the other side of) the RFelement arrangement axis 545.

The antenna 500 also includes control mechanisms 550 and 555 forcoordinating groups of RF elements. As mentioned before, it has beencontemplated that pairing opposite RF elements that are associated withdifferent spherical lens (i.e., pairing RF elements that are on oppositesides of the RF element arrangement axis) provides the optimaloverlapping vertical footprints. Thus, the control mechanism 550 iscommunicatively coupled with the RF element 520 (which is placed on topof the RF element arrangement axis 540) and the RF element 535(which isplaced on the bottom of the RF element arrangement axis 545) tocoordinate the RF elements 520 and 530 to provide signal coverage ofsubstantially the same geographical area. Similarly, the controlmechanism 555 is communicatively coupled with the RF element 525 (whichis placed on the bottom of the RF element arrangement axis 540) and theRF element 530 (which is placed on the top of the RF element arrangementaxis 545) to coordinate the RF elements 525 and 5530 to provide signalcoverage of substantially the same geographical area. In someembodiments, the control mechanisms 550 and 555 also include phaseshifters configured to modify the phase of the signals being outputtedby their associated RF elements. Thus, this embodiment has an antennaassembly that includes a control mechanism but does not include phaseshifters. Without phase shifters, the design and operation of theantenna assembly is simplified, but may have signals from outputantennas that are slightly out-of phase.

In addition to the requirement that the grouped RF elements have to beon different sides of the RF element arrangement axis, it is preferablethat the distance between the RF elements and the RF element arrangementaxis are substantially the same (less than 10%, and more preferably lessthan 5% deviation). Thus, in this example, the distance between the RFelement 520 and the axis 540 is substantially the same as the distancebetween the RF element 535 and the axis 545. Similarly, the distancebetween the RF element 525 and the axis 540 is substantially the same asthe distance between the RF element 530 and the axis 545.

While the RF elements 520 535 are shown to be placed at fixed locationsin this figure, in some other embodiments, the antenna 500 can alsoinclude tracks that enable the RF elements to move to differentpositions along the surface of their respective spherical lenses. Inthese embodiments, the control mechanisms 550 and 555 are configured tocoordinate their associated RF elements and phase shifters to send outsynchronized signals to a covered geographical area.

In the example illustrated in FIG. 5, the RF element arrangement axesare arranged to be perpendicular to the axis along which the sphericallenses are aligned. As mentioned above, the RF element arrangement axescan be oriented in different ways. FIG. 6 illustrates an antenna 600having RF elements placed on different sides of RF element arrangementaxes that are not perpendicular to the virtual axis along which thespherical lenses are aligned. The antenna 600 is almost identical to theantenna 500. The antenna 600 has an array of spherical lens (includingspherical lenses 605 and 610) that is aligned along an axis 615.Although the antenna 600 in this example is shown to include only twospherical lenses in the array of spherical lenses, it has beencontemplated that the antenna 600 can include more spherical lenses thatare aligned along the axis 615 as desired.

Each spherical lens also includes an RF element arrangement axis that isparallel to one another. In this example, the spherical lens 605 has anRF element arrangement axis 640 and the spherical lens 610 has an RFelement arrangement axis 645. As shown, the RF element arrangement axes640 and 645 are not perpendicular to the virtual axis 615. By having theRF element arrangement axes in different orientations, the antenna 600can be adjusted to cover different geographical areas (closer to theantenna, farther away from the antenna, etc.).

As shown, each spherical lens in the array has associated RF elements.In this example, the spherical lens 605 has two associated RF elements620 and 625, and the spherical lens 610 has two associated RF elements630 and 635. The RF elements associated with each spherical lens areplaced along the surface of the spherical lens, on different sides ofthe RF element arrangement axis. As shown, the RF element 620 is placedon top of (on one side of) the RF element arrangement axis 640 and theRF element 625 is placed on the bottom of (on the other side of) the RFelement arrangement axis 640. Similarly, the RF element 630 is placed ontop of (on one side of) the RF element arrangement axis 645 and the RFelement 625 is placed on the bottom of (on the other side of) the RFelement arrangement axis 645.

The antenna 600 also includes control mechanisms 650 and 655 forcoordinating groups of RF elements. The control mechanisms 650 and 655are configured to pair opposite RF elements that are associated withdifferent spherical lens (i.e., pairing RF elements that are on oppositesides of the RF element arrangement axis). Thus, the control mechanism650 is communicatively coupled with the RF element 620 (which is placedon top of the RF element arrangement axis 640) and the RF element 635(which is placed on the bottom of the RF element arrangement axis 645)to coordinate the RF elements 620 and 635 to provide signal coverage ofsubstantially the same area. Similarly, the control mechanism 655 iscommunicatively coupled with the RF element 625 (which is placed on thebottom of the RF element arrangement axis 640) and the RF element 630(which is placed on top of the RF element arrangement axis 645) tocoordinate the RF elements 625 and 630 to provide signal coverage ofsubstantially the same area. In exemplary embodiments, the controlmechanisms 650 and 655 also include phase shifters configured to modifythe phase of the signals being outputted by their associated RFelements.

FIGS. 7A and 7B illustrate an antenna similar to FIG. 3 and output areasassociated with the antenna array 700, respectively. The array 700 hasmultiple lenses (including spherical lenses 701 and 702). Although array700 in this example is shown to include only two spherical lenses in thearray of lenses, it is contemplated that array 700 can include three ormore lenses.

Each of the lenses include at least two RF elements, and twosub-controllers. In this example, the lens 701 has RF elements 720 and721, and lens 702 has RF elements 722 and 723. Each RF element has asub-controller configured for phase shifting an output beam produced bythe RF element. As shown, RF element 720 is coupled to sub-controller730, RF element 721 is coupled to sub-controller 731, RF element 722 iscoupled to sub-controller 732, and RF element 723 is coupled tosub-controller 733. Further, lens array 701 has two groupings ofassociated RF elements 720 and 722, and 721 and 723.

Each RF element generates an output beam, which is adjusted by itsassociated sub-controller, to produce an output area. In this example,the RF element 720 produce an output area 752, and the RF element 721produce an output area 751. In another embodiment, RF element the RFelement 722 produces an output area 752, and the RF element 723 producesan output area 751. In a preferred embodiment, Controller 740 cancommand the sub-controllers 730 and 732 to phase shift RF elements 720and 722, respectively, to create an overlapped beam via constructiveinterference. In a related embodiment, controller 740 can command the RFelements 720 and 722 to produce or cease production of their respectiveoutput beams based on the movement of a target. The overlapped beam fromRF elements 720 and 722 produces output area 761. As shown in outputarea grouping 750, output area 761 is narrower than output area 752, andcan be phase shifted to move about within output area 752. Controller740 can command the sub-controllers 731 and 733 to phase shift RFelements 721 and 723, respectively, to create an overlapped beam viaconstructive interference. The overlapped beam from RF elements 721 and723 produces output area 760. As shown in FIG. 7B, output area 760 isnarrower than output area 751, and can be phase shifted to move aboutwithin output area 751. The overlapped beams may operate simultaneously.The first and second overlapped may shift in concert or independently.

In certain configurations, lens 701 is collinear or non-collinear withlens 702. Additional antennas may be arranged in rows, coupled toantennas 701 and 702. Antenna rows may be parallel or non-parallel. Inother configurations, rows of antennas may be closely packed. A “closelypacked” lens arrangement may be embodied by at least two rows of lenses,clustered together such that a lens is diagonally situated from at leastone other lens in the other lens row.

FIG. 8A illustrates an embodiment of the “closely packed” antennaarrangement. Antenna array 800 is similar to antenna array 700, exceptwith additional antennas and RF elements. The array 800 has multiplelenses (including spherical lenses 701, 702, 801, and 802).

Each of the lenses include at least four RF elements, and foursub-controllers. Lens 701 has RF elements 720, 721, 816, and 817. Lens702 has RF elements 722, 723, 814, and 815. Lens 801 has RF elements810, 811, 812, and 813. Lens 802 has RF elements 818, 819, 820, and 821.

Each RF element generates an output beam, which can be adjusted by itsassociated sub-controller, to produce an output area. In preferredembodiments, each RF element has a sub-controller configured such thatwhen two beams from individual RF elements are combined, the relativephase generated by the two sub-controllers can move the position of theresulting output area within the contour of the larger output area. InFIG. 8B, the RF element 816 produces an output area 831, the RF element817 produces an output area 832, the RF element 721 produces an outputarea 751, the RF element 720 produces output area 752.

In other embodiments, the RF element 812, 814, or 820 produces an outputarea 831, and the RF element 813, 815, or 821 produces an output area832, the RF element 810, 723, or 818 produce an output area 751, the RFelement 811, 722, or 819 produce output area 752. As shown in outputarea grouping 830, the output beams from RF elements 720, 722, and 819are phase shifted to create an overlapped beam via constructiveinterference.

The overlapped beam from RF elements 721, 723, and 810 produces outputarea 760. RF elements 721, 723, and 810 can be phase shifted to trackoutput area 760 from point A to point B. Output area 760 could befurther narrowed via an additional output beam from RF element 818.Tracking output area 760 from point A to point B could be made inanticipation of a known target requiring coverage entering the outputarea 850.

An output area has a non-assigned state, where the output area is madeas narrow or wide as necessary to provide coverage to any targets thatmay enter the output area. The output beams from RF elements 816 and 812are phase shifted to create an overlapped beam via constructiveinterference. The overlapped beam from RF elements 816 and 812 producesoutput area 851. Output area 851 can be further narrowed including theoutput beams of at least one of RF elements 814 and 820 into theoverlapped beam of RF elements 816 and 812.

An output area can also track a target. In this embodiment, output area761 provides coverage to static targets 840 and 841. Output area 761 canbe narrowed to focus on either target 840 or 841 via an overlappedoutput beam from RF element 811, 722, and 819. In other embodiments, anoutput area 850 tracks a dynamic target 842 (e.g. a satellite) across anarea of sky to point C. The output beams from RF elements 817, 813, 821,and 815 are phase shifted to create an overlapped beam via constructiveinterference. This overlapped beam produces output area 850. Output area850 is further phase shifted to track and provide coverage to target842.

An output area provides an area of signal coverage in at least a portionof the sky or outer space. The dimensions of an output area can beuser-inputted or autonomously generated via a controller 740. Eachoutput area can be static or dynamic. Dynamic output areas can changeaccording to variables, such as time or environmental conditions.

FIG. 9 illustrates another embodiment of the “closely packed” antennaarrangement. Antenna arrangement 900 is similar to antenna array 800,except the antenna arrangement 900 is configured for discriminatingtargets via phase shifters to place output beams in specific locations,rather than real time beam movement with targets. This approach is moreamenable for tracking multiple targets simultaneously. The array 900 hasmultiple lenses (including spherical lenses 905, 920, and 925). Althoughantenna arrangement 900 in this example is shown to include only threespherical lenses, it is contemplated that antenna arrangement 900 caninclude four or more lenses. In a preferred embodiment, at least a firstlens is positioned to provide coverage for an area of sky different fromthe area of sky serviced by a second, different lens. In exemplaryembodiments, the lenses of antenna arrangement 900 are spherical. Inalternative embodiments, at least one of the lenses of antennaarrangement 900 is non-spherical.

Each of the lenses includes at least four RF elements, onesub-controller, and one receiver. Lens 905 has RF elements 906, 907,908, and 909. Lens 920 has RF elements 921, 922, 923, and 924. Lens 925has RF elements 926, 927, 928, and 929. Each lens has a sub-controllerconfigured for combining a first output beam produced by first RFelement with a second output beam produced by a second RF element. Asshown, lens 905 is coupled to sub-controller 910, lens 925 is coupled tosub-controller 911, and lens 920 is coupled to sub-controller 912.

An output area can have a fixed position, where the output area isdirected toward a single area of sky to provide coverage to any targetsthat may enter the output area. The output beam from RF element 907 isactivated to create output area 940 to provide coverage for dynamictarget 941 (e.g. a satellite) within output area 940. The footprint ofoutput area 940 is depicted as a circle. An output area can also track atarget in between the output areas (e.g. circular footprints) generatedvia any single RF element. In an exemplary embodiment, RF elements 926and 927 are activated to create combined output area 943 in order totrack dynamic target 944 across an area of sky from point C in outputarea 945 to point D in output area 942. The output beams from RFelements 926 and 927 are combined to create a combined output area viaconstructive interference. The output beam from RF element 926 isactivated to create output area 945, and output beam from RF element 927is activated to create output area 942. Advantageously, a combinedoutput area facilitates the smooth transition for tracking a satellitefrom the output area of a one RF element to another output area ofanother, different RF element.

In a related embodiment, RF elements 921, 922, and 923 are activated tocreate combined output area 948 in order to track dynamic target 949 asit travels in the gap between output area 946, output area 947, andoutput area 950. The output beams from RF elements 921, 922, and 923 arecombined to create a combined output area via constructive interference.The output beam from RF element 923 is activated to create output area946, the output beam from RF element 921 is activated to create outputarea 947, and the output beam from RF element 922 is activated to createoutput area 950.

In certain configurations, RF elements may be arranged in rows andcolumns, coupled to their respective lenses. RF element rows may beparallel or non-parallel. In other configurations, rows of RF elementsmay be closely packed. A “closely packed” RF element arrangement may beembodied by at least two rows of RF elements, clustered together suchthat an RF element is diagonally situated from at least one other RFelement in the other RF element row. Spacing between RF elements isconfigured to be a dense arrangement so as to minimize gain loss in gapsbetween output beams.

Each dynamic target (of the dynamic targets tracked by RF elementsassociated with antenna arrangement 900) is assigned (or alternatively,communicatively coupled with) a receiver for communication with thedynamic target. In a preferred embodiment, controller 930 is configuredfor assigning a receiver to a target. Controller 930 may also reassignreceivers and RF elements as a target is tracked across an output area.In exemplary embodiments, dynamic target 941 is assigned to receiver931, dynamic target 944 is assigned to receiver 932, and dynamic target949 is assigned to receiver 933. In exemplary embodiments, each dynamictarget is assigned a single receiver. In alternative embodiments, two ormore targets may be assigned to a single receiver, where the controller930 will direct the single receiver to rapidly switch coverage betweenthe plurality of targets. Each receiver is configured to receive from atarget. In exemplary embodiments, each target is assigned a receiver. Inaddition, the RF elements of antenna arrangement 900 are configured toreceive/detect incoming signals that have been focused by theirassociated lenses.

As shown, the lenses of antenna arrangement 900 are aligned along avirtual plane. In some embodiments, the virtual plane is parallel to theground on top of which the antenna arrangement 900 is disposed. FIG. 9shows an isometric projection of antenna arrangement 900, which depictsthe array disposed above the ground. In preferred embodiments, thecontroller, sub-controllers, and receivers are disposed between thelenses and the ground. In alternative embodiments, at least one of thecontroller, sub-controllers, and receivers is aligned along the samevirtual plane as the lenses of antenna arrangement 900. In yet anotherembodiment, at least one of the controller, sub-controllers, andreceivers is aligned along a virtual plane different from that virtualplane along which the lenses of antenna arrangement 900 are aligned.

FIG. 10 illustrates the inventive concept for a three beam, three lensstaggered array. The lenses and elements feeding the array 1000 arearranged along their virtual axis' with the exception of a 30 mm staggerhorizontally from the virtual axis of one lens to the virtual axis of adifferent lens. In an exemplary embodiment, there are a total of ninedual polarized elements for a total of 18 antenna ports, each with acolumn of three elements for a given polarization arrayed using a 1:3phase shifter, so the array 1000 has three dual polarized beams. Antennaarray 1000 is similar to antenna system 100, and includes an additionalspherical lens 1010, which along with lens 1001 and 1005, are eachaligned along a different virtual axis in a three-dimensional space. Thearray 1000 has multiple lenses (including spherical lenses 1001, 1005,and 1010). Each of the lenses includes at least one RF element. Lens1001 has RF element 1002. Lens 1005 has RF element 1006. Lens 1010 hasRF element 1011.

In other embodiments, a second column of lenses and elements can be usedto achieve 4×4 MIMO. In a preferred embodiment, the output beams ofarray 100 have their azimuth on the horizon. In a related embodiment,the output beams of array 100 are down-tilted beams, such that each RFelement is rotated about the lens center to position the beams tocoincide with the desired down tilt.

The lenses of array 1000 can be any shape and any combination of singleor multiple dielectric constant layers. Lens based antenna arrays havethe advantage of negligible grating lobes for array spacings (e.g. thespacing between lenses), which are larger than certain other traditionalantennas due to the much narrower pattern from the individual lenses.This lens spacing allows the positions of the lens to be varied toreduce the azimuth SLL, as depicted by FIG. 10. In a preferredembodiment, the array 1000 has an Azimuth SLL ranging from 25-30 dB,which approximately correlates to a 12-15 dB improvement in the AzimuthSLL of a Butler Matrix based antenna.

FIGS. 11A-11C provide three perspectives of array 1100: top (11A), front(11B), and side (11C). In a preferred embodiment, the virtual axis'(1007 and 1012) through lens 1005 and lens 1010 are offset from thevirtual axis 1003 of lens 1001 by 30 mm. In a related embodiment, thelens 1005 has a virtual axis 1008 located 30 mm left from virtual axis1004, and the lens 1010 has a virtual axis 1013 located 30 mm right fromvirtual axis 1004. In some embodiments, there is separation of 25 mmbetween the boresight virtual axis 1003 of lens 1001 and the boresightvirtual axis 1007 of lens 1005.

FIG. 12 illustrates an embodiment of array 1000. The largest side lobesfor the center output beam in the azimuth plane occur at approximately+/− 40 degrees from the boresight virtual axis' (1007, 1003, and 1012),and are depicted by arrows for simplicity. The staggered spacing of thelenses is a function of the distance between at least two of the virtualaxis' 1007, 1003, and 1012, and can be calculated by vector addition. Ina preferred embodiment, lens 1001 is fed an amplitude equivalent to 1volt, while lenses 1005 and 1010 are each fed amplitudes equivalent to0.7 volts. In some embodiments, lenses 1005 and 1010 operate at halfpower, such that together they equal the power of lens 1001. Inpreferred embodiments, the stagger modifies the relative phase betweenthe lenses 1001, 1005, and 1010 to create destructive interference andreduce the side lobes (SLL) in the +/− 40 degree directions.

In a related embodiment, additional phase compensation is utilized toproduce a similar reduction in side lobes for the output beamspositioned at +/− 40 degrees. In some embodiments, the RF elementsproducing the side beams will be phase delayed or phase progressed tobring the array of lenses into a coherent phase front in the directionof the beam peak (i.e. +/− 40 degrees).

Graph 2 depicts the vertical patterns used for an output beam directedalong a virtual axis. Graph 2 illustrates an embodiment where theintroduced stagger has negligible impact on the elevation pattern.

Graph 3 illustrates azimuth patterns for three beams configured forco-pol and x-pol at a 45 degree slant polarization, with the side lobesreduced to approximately 26 dB, which provides a 14 dB improvementcompared to Graph 1 (i.e. FIG. 6 of U.S. Pat. No. 8,311,582 to Triguiet. al). The 10 dB beam width level ranges from 42 to 45 degrees overthe 3.7 to 4.0 GHz band, consistent with around an 8 dB cross over levelbetween the output beams spaced 40 degrees apart.

FIGS. 13A and 13B illustrate another embodiment of the array 1000, andinclude an additional spherical lens 1030, which along with lenses 1001,1005 and 1010, are each aligned along a different virtual axis in athree-dimensional space. As each of the lenses includes at least one RFelement, lens 1030 has RF element 1031. Advantageously, thisconfiguration of array 100 has a mechanically balanced structure whichincludes the added benefits of less complicated construction, and adoubling of the azimuth side lobe level reduction provided by a firstlens to a second lens located above or below the first lens.

FIG. 14 illustrates a three beam, three lens staggered array 1400 withmaterial blocks. Advantageously, outer beam side lobes (SLL) that occurat roughly +/−90 degrees from the peak of an output beam produced by RFelement 1406 are reduced by the coupling of certain lenses to materialblocks in array 1400. In a preferred embodiment, material block 1407 ispositioned such that a side lobe of an output beam produced by RFelement 1406 can travel along an edge of material block 1407.Advantageously, this has the effect of reducing the azimuth SLL in thedirection of the output beam produced by RF element 1406, and a reducingthe impact on the pattern performance of array 1400. In someembodiments, material block 1407 comprises a dielectric material withpermittivity 2.5, a thickness of 30 mm, a height of 150 mm, and a depthof 110 mm. In a preferred embodiment, the phase delay generated bymaterial block 1407 to reduce the azimuth SLL of the output beamproduced by RF element 1406 is a function of the dielectric permittivityand thickness of material block 1407. In some embodiments, materialblock 1407 is positioned with lens 1405 and lens 1410. In relatedembodiments, material block 1407 is positioned 30 mm from the surface oflens 1405. Material blocks 1407 and 1411 can comprise a dielectric ofisotropic or anisotropic material. Antenna array 1400 is similar toantenna system 1000, and includes material blocks 1407 and 1411, whichare aligned with lenses 1405 and 1410, respectively. The array 1400 hasmultiple lenses (including spherical lenses 1401, 1405, and 1410). Eachof the lenses includes at least one RF element. Lens 1401 has RF element1402. Lens 1405 has RF element 1406. Lens 1410 has RF element 1412,which is not shown for simplicity.

FIG. 15 illustrates an antenna similar to FIG. 7A and output areasassociated with the antenna array 700, except each lens has a singleradiating element. The antenna array 1500 has multiple lenses (includingspherical lenses 1505 and 1510). Although array 1500 in this example isshown to include only two spherical lenses in the array of lenses, it iscontemplated that array 1500 can include three or more lenses.

Each of the lenses include at least one RF element, and at least onesub-controller. In this example, the lens 1505 has RF element 1506, andlens 1510 has RF element 1511. Each RF element has a sub-controllerconfigured for the phase of output beam produced by the RF element. Asshown, RF element 1506 is coupled to sub-controller 1507, and RF element1511 is coupled to sub-controller 1512.

Each RF element generates an output beam In this example, the RF element1506 produces an output area 1508, and the RF element 1511 produces anoutput area 1513. In a preferred embodiment, controller 1515 can commandthe sub-controllers 1507 and 1512 to adjust the phase of the outputbeams produced by RF elements 1506 and 1511, respectively, to create anoverlapped beam. In a related embodiment, controller 1515 can commandthe RF elements 1506 and 1511 to produce or cease production of theirrespective output beams based on the movement of a target.

FIG. 16 illustrates another embodiment of the antenna arrangement ofFIG. 15. Antenna arrangement 1600 is similar to antenna array 900,except the antenna arrangement 1600 is configured for tracking ofdynamic targets via beam switching, rather than beam combination. Thearray 1600 has multiple lenses (including spherical lenses 1505, 1510,1610, 1612, 1615, 1617, and 1619). Although antenna arrangement 1600 inthis example is shown to include only seven spherical lenses, it iscontemplated that antenna arrangement 1600 can include eight or morelenses. In a preferred embodiment, at least a first lens is positionedto provide coverage for an area of sky different from the area of skyserviced by a second, different lens. In exemplary embodiments, thelenses of antenna arrangement 1600 are spherical. In alternativeembodiments, at least one of the lenses of antenna arrangement 1600 isnon-spherical.

Each of the lenses includes at least one RF element, and onesub-controller. Lens 1505 has RF element 1506, lens 1510 has RF element1511, lens 1610 has RF element 1611, lens 1612 has RF element 1614, lens1615 has RF element 1616, lens 1617 has RF element 1618, and lens 1619has RF element 1620. Each lens has a sub-controller configured forcombining a first output beam produced by first RF element with a secondoutput beam produced by a second RF element to produce a firstoverlapped beam as a function of the phases of each output beam.

An output area can have a fixed position, where the output area isdirected toward a single area of sky to provide coverage to any targetsthat may enter the output area. In a preferred embodiment, the outputbeam from RF element 1506 is activated to create output area 1601. Aslens 1505 is spherical, the footprint of output area 1601 is depicted asa circle. In an exemplary embodiment, RF elements 1506, 1511, 1611,1614, 1616, 1618, and 1620 produce output area 1601. By combining usingdifferent relative phase, that is achieved by combining fixed lengths oftransmission line, output areas 1508, 1606, 1513, 1604, 1603, 1602, 1605are produced. Advantageously, a configuration of multiple output areasfacilitates the smooth transition for tracking a satellite from oneoutput area to another. For illustration purposes only the output areascan be thought of as representing the 10 dB three dimensional patternpower contour plot.

In an exemplary embodiment, lens 1506 is a a 500 mm diameter sphericallens, operating at 8 GHz, where the 10 dB beam width contour from lens1506 will have approximately a 2.5 degree beam width. In a relatedembodiment, the output areas 1508, 1513, 1602, 1603, 1604, 1605, and1606, all are configured for 10 dB output beam contours withapproximately ⅓ the beam width of the output beam for output area 1601(e.g. 0.8 degrees). In a preferred embodiment, the position of eachoutput area is determined by the relative phase between the seven lensesin the array 1600. In certain embodiments, the relative phase between RFelements is typically provided by the sub-controller via a power dividernetwork. The concept of creating a set of 7 output areas, each havingbeam widths approximately ⅓ of the beam width of each individual lenscan be scaled to create even smaller output areas for more precisetracking. As an example, the output area 1513, which itself is createdby a specific set of combining output areas from lenses 1505, 1511,1611, 1614, 1616, 1618, and 1620, can be created by combining outputareas from 6 other clusters of lenses (not shown).

In some embodiments, the array 1600 is configured as a receive onlyarray. In another embodiment, array 1600 is a transmit and receive(TX/RX) system, where sub-controller that diplexes the transmit signalfrom the controller receives such the receive signal, amplifies thereceive signal by an LNA and the transmit signal by a power amplifier,then recombines the signals to produce a single output beam fortransmission and reception.

There are a number of lens configurations for combining RF signals froma seven lens cluster to form the output areas of array 1600. In apreferred embodiment, multiple dual polarized RF elements are tightlypacked near the surface of a lens, where the lens is typically sphericalin shape. Advantageously, this approach provides the ability to cover alarge portion of the sky with a single set of lenses, each lenssurrounded by numerous RF elements.

FIG. 17 illustrates an antenna similar to FIG. 10, intended to producebeams in a horizontal direction, except the lenses are colinear and eachRF element has a 4.5-degree tilt. The antenna array 1700 has multiplelenses (including spherical lenses 1701 and 1702). Each of the lensesinclude at least one RF element. In this example, the lens 1701 has agroup of three RF elements 1705, and lens 1702 has a group of three RFelements 1706. In a preferred embodiment, the RF elements of lenses 1701and 1702 are spaced forty degrees apart to provide coverage over three40-degree sectors for complete coverage over a traditional 120 degreesector. Each RF element within the array 1700 has a slight 4.5-degreetilt, such that each output beam generated by the array 1700 is tiltedin the vertical plane of 4.5 degrees. Although array 1700 in thisexample is shown to include only two spherical lenses in the array oflenses, it is contemplated that array 1700 can include three or morelenses. FIG. 17 is an example of the concept of “pre-tilt” discussedabove as a further means to reduce the upper grating lobes.

It should be evident that there are three interchangeable techniques; 1)moving the feed with tilt, 2) providing a pre-tilt, 3) keeping the feedfixed and allowing just the phase shifter to provide the beam tilt. Anycombination of these three techniques can be used not just for a givenarray, but different combinations of techniques can be used within thearray 1700. In an embodiment, the array 1700 is configured to allow themiddle element of an array to move but keep the upper and lower elementsfixed with beam tilt. In a related embodiment, the array 1700 isconfigured to vary the pre-tilt from element to element, the top elementhaving a 3 degree pre-tilt and each successive element having 0.5 degreeless pre-tilt. The present invention is based on the recent advances inmeta materials (U.S. Pat. No. 8,518,537) and is a further extension ofthe initial patent issued for arraying together lens antennas usingplane waves (U.S. Pat. No. 9,728,860).

Graph 4 depicts a phase shifter to apply a relative phase between twoin-line RF elements in the vertical plane to produce a resulting arrayedbeam (or overlap beam). The phase shifter provides equal phase,representing zero degree down tilt, resulting in the Graph 4 beampattern.

As illustrated above, the peak of the main beam in Graph 4 is at zerodegrees, and main beam position is determined firstly by the relativephase between two RF elements. Advantageously, the first upper side lobeis −15 dB down from main beam peak. Without the “pre-tilt” technique thefirst upper side lobe would be around 11-12 dB The third feature tonotice is the first lower side lobe is around −7.5 dB. This is again dueto the “pre-tilt” but as mentioned above.

Graph 5 depicts the vertical pattern of a single RF element in atwo-element array.

The beam pattern of Graph 5 illustrates RF element lacking “pre-tilt”,but pointed along the horizon.

Graph 6 depicts the beam pattern generated by an RF element configuredfor 4.5 degrees of pre-tilt.

As a result of the beam peak being down tilted in Graph 6, the powerlevel at zero degrees is around −0.25 dB, and represents the boresightgain loss impact due to this technique. If less than 4.5 degree of“pre-tilt” is used this gain loss will be reduced. Further, the powerlevel at 20 degrees above the horizon is −9.6 degrees, or 3.6 degreeslower than without pre-tilt.

It should be noted that when the feeds are rotated for different downtilts the pre-tilt is maintained. In a preferred embodiment, a 15 degreetilt with 4.5 degree pre-tilt results in each RF element tilting 19.5degrees relative to the horizon. Advantageously, this pre-tiltingtechnique is not frequency sensitive, and can be used with equaleffectiveness over any frequency band. In a related embodiment, the RFelements are configured in a fixed position, with the beam tilt beingadjusted only with changing the relative phase between RF elements byuse of a phase shifter.

FIG. 18 illustrates a three- lens antenna similar to FIG. 17, excepteach RF element has a 8-degree tilt. The antenna array 1800 has multiplelenses (including spherical lenses 1805, 1810, and 1815). Each of thelenses include at least one RF element. In this example, the lens 1805has RF element 1806, lens 1810 has RF element 1807, and lens 1815 has RFelement 1808. Graph 7 depicts the beam pattern for 8 degrees of downtilt as generated by array 1800.

As shown above, and in preferred embodiments, the electrical down tiltmatches the physical tilting of the RF elements of array 1800. Here, thefirst upper side lobes range between a nominal 19 dB to −14 dB.

Graph 8 depicts a beam pattern where the elements remain fixed at 8degrees, but the relative phase between RF elements is set for a 4degree down tilt, showing the limit of keeping the RF elements in afixed position.

FIG. 19 illustrates an antenna system 1900 which includes spherical RFlens 1910 and RF element 1915. In certain embodiments, the RF element1915 is configured as a single dual polarized dipole. In a preferredembodiment, the phase center of RF element 1915, which occursapproximately at the location of the dipole ground plane, is placed atthe focal point of the RF lens 1910.

Graph 9 depicts a typical azimuth pattern for the RF element 1915described in FIG. 19. Here, the worst side lobe is −19.3 dB.

FIG. 20 illustrates an antenna system 2000 according to some embodimentsof the inventive subject matter. In this example, the antenna system2000 includes RF lens 1910 and Dual RF element 2010. In a preferredembodiment, Dual RF element 2010 comprises RF element 1915 and RFelement 2015. Antenna arrangement 2000 is similar to antenna array 1900,except for the two RF elements placed in close proximity to each other.This creates an illumination on the lens closer to the desired Gaussianillumination. In a preferred embodiment, RF element 1915 and RF element2015 should be distanced from each other by a half wavelength, asmeasured from phase center to phase center.

Graph 10 depicts the revised azimuth pattern for the Dual RF element2010 described in FIG. 20, where the worst side lobe is −25.7 dB—animprovement of 6.4 dB from Graph 9. This level of improvement issignificant as it directly correlates to signal to interference plusnoise plus ratio (SINR). To achieve higher data rates used in 5Gwireless networks such as 64 QAM and 256 QAM higher SINR is needed. In apreferred embodiment, by lowering side lobes via Dual RF element 2010,interference from adjacent sectors is reduced, improving SNIR.

It should be apparent to those skilled in the art that many moremodifications besides those already described are possible withoutdeparting from the inventive concepts herein. The inventive subjectmatter, therefore, is not to be restricted except in the spirit of theappended claims. Moreover, in interpreting both the specification andthe claims, all terms should be interpreted in the broadest possiblemanner consistent with the context. In particular, the terms “comprises”and “comprising” should be interpreted as referring to elements,components, or steps in a non-exclusive manner, indicating that thereferenced elements, components, or steps may be present, or utilized,or combined with other elements, components, or steps that are notexpressly referenced. Where the specification claims refers to at leastone of something selected from the group consisting of A, B, C . . . andN, the text should be interpreted as requiring only one element from thegroup, not A plus N, or B plus N, etc.

What is claimed is:
 1. A communication system, comprising: at least afirst lens; the first lens has a first RF element oriented to produce afirst output beam, and a second RF element oriented to produce a secondoutput beam; wherein the first RF element is configured for a firstphase, and the second RF element is configured for a second phase; acontroller configured to combine at least the first output beam and thesecond output beam to produce a first overlapped beam, by constructiveinterference; wherein the first overlapped beam is produced as afunction of the first phase and the second phase.
 2. The communicationsystem of claim 1, further comprising a second lens having a third RFelement oriented to produce a third output beam, and a fourth RF elementoriented to produce a fourth output beam; and wherein the third RFelement is configured for a third phase; and the fourth RF element isconfigured for a fourth phase.
 3. The communication system of claim 2,wherein the controller is further configured to combine at least thethird output beam and the fourth output beam to produce a secondoverlapped beam, by constructive interference.
 4. The communicationsystem of claim 2, wherein the controller is further configured tocombine at least the first overlapped beam and the third output beam toproduce a second overlapped beam.
 5. The communication system of claim1, wherein at least the first RF element and the second RF element areseparated by a distance.
 6. The communication system of claim 1, whereinthe first phase is different from the second phase.
 7. The communicationsystem of claim 2, wherein at least one of the first lens and the secondlens are spherical.
 8. The communication system of claim 1, wherein thefirst RF element and the second RF element are configured for a sharedground plane.
 9. The communication system of claim 1, wherein at leastof the first RF element and the second RF element is configured for aseparate ground plane.
 10. The communication system of claim 1, whereinthe first output beam is different from the second output beam.
 11. Thecommunication system of claim 1, wherein the first output beam isconfigured for a first beam width, and the second output beam isconfigured for a second beam width.
 12. The communication system ofclaim 11, wherein the first beam width is the same as the second beamwidth.
 13. The communication system of claim 11, wherein the first beamwidth is different than the second beam width.